Modified version that https://github.com/technmsg wrote.

slack_delete

slack_delete allows you to delete files from Slack in bulk. If you are on a free Slack plan, you can only have so many files and use up so much space. After a while, this tends to fill up.

Reasons For My Version

I decided to modify this script for a few reasons:

1. there was an extraneous call to json.loads() that kept it from running properly
2. python3 support
3. rate limiting to follow Slack's suggestions (https://api.slack.com/docs/rate-limits)

Requirements

This uses the requests library that you'll need to install (probably best done in a virtual environment)

python3 -m pip install requests

You will also need to know your slack token, which you can find or create at https://api.slack.com/docs/oauth-test-tokens

Usage

usage: slack_delete.py [-h] -t TOKEN [-d DAYS] [-c COUNT]

optional arguments:
  -h, --help            show this help message and exit
  -t TOKEN, --token TOKEN
                    Specifies the OAuth token used for authentication,
                    created at (https://api.slack.com/docs/oauth-test-
                    tokens)
  -d DAYS, --days DAYS  Delete files older than x days (optional)
  -c COUNT, --count COUNT
                    Max amount of files to delete at once (optional)

Example Run

python3 slack_delete.py --token yourtokengoeshere -d 90